Electron discharge device



Nov. 17', 1959 J. K. LENNARD ELECTRON nzscmsz DEVICE 2 Sheets-Sheet 1' Filed Oct. 29, 1957 [n 1 8]? tor- Jae/(K L ennara J. K. LENNARD 2,913,609

ELECTRON DISCHARGE DEVICE Nov. 17, 1959 Filed Oct. 29, 1957 2. Sheets-Sheet f1? Mental 1- fac/f L 627178121,

2,913,609 ELECTRON DISCHARGE DEVICE Jack K. Lennard, Fort Wayne, Ind., assignor to International Telephone and Telegraph Corporation Application October 29, 1951, Serial No. 693,049 1s Claims. c1. 313-35) This invention relates to electron discharge devices and more particularly to an arrangement for cooling an electrode of such device.

7 Many electron discharge devices, such as vacuum tubes, X-ray tubes, certain photosensitive tubes and storage tubes contain an electrode which is heated by bombardment of electrons from a cathode. This heating reduces the overall efliciency of the device and limits the maximum power which can be dissipated or controlled by the device. As in the case of other electrical devices subject to heating, cooling of the electrode to extract the heat therefrom improves the overall efiiciency of the device and permits operation of the device at higher power levels. In the past, efforts have been made to cool electron discharge devices by such means as external cooling fins, forced air circulation over the device, or by the use of, external cooling coils or jacketssurrounding the exterior surface of the device and through which a coolant, such as water, is passed. Such external methods of cooling have, however, been relatively inefficient. Certain large transmitting tubes have been internally cooled by means of cooling coils or jackets surrounding the electrode subject to heating, generally the plate, with a coolant, generally cooled water, being circulated through such cooling coils or jackets. Such prior internal cooling arrangement, however, required external water connections, and accompanying seals, and were generally relatively expensive and cumbersome, thus limiting such internal cooling arrangements to relatively large devices. In addition, with the conventional water cooling of'electron discharge devices, eitherinternal or external, the heat extraction permissible was limited by the heat extracting capabilities of water.

It is therefore desirable to provide a structure for internally cooling the electrode of an electron discharge device which. may be utilized in smaller devices than could heretofore be cooled by internal water cooling arrangements. It is further desirable that such a cooling arrangement permit cooling of the electrode to temperatures substantially lower than provided by water cooling and it is further desirable that such cooling arrangements be relatively simple and foolproof.

In practicing my invention, I utilize one or more Joule- Thomson effect cooling devices disposed within the electron discharge device and abutting the electrode to be cooled; these Joule-Thomson effect cooling devices will 2,913,609 Patented Nov. 17,

ice

2 I electron discharge device incorporating a Joule-Thomson effect cooling device for directly cooling an electrode.

The above mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunctionwith the accompanying drawings, wherein:

' Fig. 1 is a cross-sectional view illustrating a form of Joule-Thomson effect cooler suitable for use in my'invention; Fig. 2 is a fragmentary view illustrating a portion'of the coiled coil capillary tubing employed in the cooler of Fig.1; i V Fig. 3 is a cross-sectional view of one form of electron discharge device employing a single Joule-Thomson effect cooler for cooling the anode; 3 v I Fig. 4is a perspective view, partially broken away,

' showing a structure employing a plurality of Joule- Thornson effect coolers for cooling an electrode of an electron discharge device; Fig. 5 is a fragmentary cross-sectional View of the electron discharge device of Fig. 4;. H Fig. 6 is a cross-sectional view illustrating a modified form of my invention, employing a pluralityof Joule- Thomson eflect coolers for cooling the electrode of an electron discharge device;

Fig. 7 is a perspective view illustrating another modification of this invention employing a single Joule- Thomson effect cooler embracing an electrode of an I electron discharge device, such as the target electrode of a barrier grid storage tube; p v Fig. 8 is a fragmentary perspective view illustrating the employment of a Joule-Thomson efiect cooler of the type shown in Fig. 7 for cooling the plate of a vacuum tube; Fig. 9 is a fragmentary schematic cross-sectional view illustrating the employment of a plurality of Joule- Thomson effect coolers for cooling the target electrode of a storage tube;

Fig. 10 is a perspective view illustrating the target and cooler assembly of the tube of Fig. 9;

provide temperatures as low as minus 196 C. and occupy v Fig. 11 is a view in perspective illustrating another form of electrode and cooler assembly in accordance with my invention; and

Fig. 12 is a fragmentary perspective view, partly in section, illustrating yet another application of my invention.

Referring now to Figs. 1 and 2, a typical form of Joule- Thomson effect device includes a thin-wall tube or jacket 1 having a closed lower end 2 and an upper end 3 open to the atmosphere. Jacket 1 may be formedofsuitable metal, such as stainless steel. Entering'the jacket 1 is a small capillary tube 4 which extends downwardly in the jacket 1 in a coiled coi configuration 5, as better shown in Fig. 2, terminating in a small nozzle 6. The capillary tubing 4 may be formed of .020 inch stainless steel tubing and the nozzle 6 may be .010 inch in diam-. eter. Nitrogen under high pressure, such as on the order of 3,000 pounds per square inch is supplied to the capillary tube 4 and is expanded through the nozzle 6. This expansion of the nitrogen causes initial cooling and the nitrogen then flows upwardly, as indicated bythe arrow 7, over the convolutions of the coiled coil 5, thus extracting further heat from the tubing. The nitrogen is finally exhausted to the atmosphere through the opening 3. Joule-Thomson effect cooling devices, of the types shown in Figs. 1 and 2, are capable of producing j photo-tube, having a glass envelope 9 with a photoemissive cathode 10 deposited on the interior surface of the end 11 of the tube. An anode 12, which may be a flat annular relatively thin copper plate is disposed within the envelope 9 and spaced from the photosensitive cathode 10, Inorder to extractheatfromthe anode 12, a Joule- Thomsoneffect cooler 1310f the-type shown in Figs. 1 and .2 is disposed within the envelope 9 with its cold end 2 abut ing the surface 14 of the anode 12 remote from the photosensitive cathode 10. A low pressure nitrogen exhaust conduit 15 is secured to the end 16 of the jacket 1 of the Joule-Thomson effect cooler 13 and passes through the wall of the envelope 9, as shown, with a suitable seal beingformed as is well known in the art. The high pressure nitrogen line 4 is brought out coaxially within the discharge conduit 15 as shown. The photo- Sensitivecathode 1,0 and anode 12 are shown as having external leads 17 and 18 respectively connected thereto and brought out through the wall of envelope 9 by suit able seals, however it willbe readily understood that anyconventional method of bringing out the electrical cohnections to the photosensitive cathode and anode may be employed and further that the anode 12 and Joule- Thomson effect .cooler 13 may be mounted and sup 1 ported within the envelope 9 in any convenient manner.

Referring now to Figs. 4 and 5, again, an electrode 19, which may be an anode, is disposed within an envelope 20, shown here in dashed lines, of an electron discharge device. Here, in order to provide sufficient heat extraction'fr'om theanode 19, a plurality of Joule-Thomson effect coolers 21 through 24 respectively have their cold ends 2 abutting the bottom surface 25 of theanode 19. In the arrangement of Fig. 4, the connection for the low pressure nitrogen discharge and high pressure nitrogen inlet' to'the individual Joule-Thomson effect coolers 21 throq h'24 is provided by a header assembly 26. Header assembly 26 includes an annular bottom portion 27 having an annular groove 28 formed therein. An annular upper portion. 29 is provided abutting the upper surface of .themember 27 and having a diameter slightly greater than the outside diameter of the groove 28 thereby covering the groove 28 to form an annular passage. The upper member 29 has a plurality of downwardly extending openings 30 formed therein respectively communicating with the high pressure tube 4 of the Joule-Thomson effect coolers 21 through 24 and with the annular groove 28 in the bottom portion 27. A high pressure nitrogen inlet line 331 communicates with the groove 28 and is brought out through the envelope 20 by any suitable sealing arrangement. Surrounding the portion 29 is an outer portion 32 having an annular groove 33 formed in -its lowersurface adjacent its inner edge. Portion 32 is also arranged abutting the upper surface of the portion 27 and with its 'inner surface abutting the outer surface of inner'portion 29 so that the groove 33 forms a second annular passage. A plurality of downwardly extending passages 33 and 34 are formed in the portion 32 communicating with the low pressure discharge outlets 3 of the Joule-Thomson effect coolers 21 through 24 and the passage 33, and'a low pressure nitrogen discharge line 35 communicates with the passage 33 and is brought out through the wall of the envelope 20 by any conventional sealing means. It is thus seen that a single high pressure inlet line 31 and a single low pressure exhaust line 35 respectively supply the nitrogen to and exhaust the low pressure nitrogen from the plurality of Joule-Thomson effect coolers 21 through 24 by means of the header assembly 26.

Referring now to Fig. 6 in which like elements are indicated by like reference numerals, modification of the embodiment of Figs. 4 and 5 is shown in which the header assembly 26 of Figs. 4 and 5 is eliminated and here it will be seen that the bottom surface 25 of the anode 19, which may be formed of copper, may form the cold-end closure of the jackets of the Joule-Thomson cooling devices 22 and 24 and that the low pressure ends 36 may communicate with a common low pressure discharge duct 37 which in turn communicates with the low pressure discharge line 35. Here, thehigh pressure nitrogen inlet line 31 is again brought into the envelope 20 coaxially through the low pressure nitrogen discharge line 35 and in this case is connected to the individual capillary cooling coils 5 by means of soldered connections, as at 38.

Referring now to Fig. 7, there is shown a fiat annular electrode 39:, for example formed of relatively thin copper sheet; the electrode'39 may for example be a target electrode of a storage tube or may again be an anode of some other electron discharge device. Here, a single Joule- Thomson effect cooler 40 is arranged in a semi-circular configuration embracing the outer periphery of the electrode 39 as shown. It will be seen that the warm end 41 of the Joule-Thomson effect cooler 40 is spaced from the outer periphery of the electrode 39 in order that the colder portion of the cooler adjacent the cold end 42 may more efficiently extract heat from the electrode 39. A low pressure nitrogen discharge line 43 is attached to the warm end 41 of the Joule-Thomson effect cooler 40 with the high pressure nitrogen inlet 44 being coaxially arranged within the low pressure discharge line 43.

Referring now to Fig. 8, in which like elements are again indicated by like reference numerals, it will be seen that the semi-circular shaped Joule-Thomson effect cooler 40 is arranged embracing a cylindrical electrode 45, which may be the plate of a vacuum tube having a cylindrical cathode ,46 and a control grid 47 disposed in conventional manner as shown. Here again, the warm end 41 of the Joule-Thomson effect cooler 40 is spaced from the outer periphery of the plate 45 for more efficient cooling. It will be readily understood thata plurality of semi-circular shaped Joule-Thomson coolers 40 may be disposed on the outer periphery of the plate 45 with the low pressure discharge and high pressure nitrogen inlet lines being connected by a header arrangement. Referring now to Figs. 9 and 10, there is shown a storage tube, generally identified as 48, having an envelope 49 with an electron gun assembly 50, which may be of any conventional design, disposed adjacent one end thereof. The electron gun 50 provides an electron beam 51 which is focused and caused to scan the target electrode 52 by means of any conventional focusing and defleeting system, such as external focusing and deflecting coils 53. The target 52 may be directly viewed by means of a suitable optical system 54, however, it will be readily understood that the storage tube 48 may be provided with a conventional electronic output system; it will be readily understood that the general construction of the storage tube 48 does not form a part of this invention and is shown for illustrative purposes only. In order to provide for cooling of the target electrode 52 and at the same time permit optically viewing or electronically reading out the stored information from the side 55 remote from the electronic gun 50, a plurality of Joule-Thomson effect coolers 56 through 59, inclusive, are provided having a frusto-conical arrangement as best seen in Fig. 10. Here again, the cold ends 60 of the Joule-Thomson effect coolers 56 through .59 abut the bottom surface 55 of the target electrode 52 and their warm ends 61 are respectively joined by a toroidal-shaped header member 62 which may be constructedin a manner similar to the header 26 of Fig. 4 or the header 37 of Fig. 6. Low pressure discharge line 63 and high pressure nitrogen inlet line 64 communicate with the header member .62, it being understood that the high pressure nitrogen inlet line 64 may be brought out coaxially within the low-pressure nitrogen discharge line 63.

Referring now to Fig. 11 in which like elements are again indicated by like reference numerals, it will be seen that the arrangement of Figs. 9 and 10 is modified for use with a cylindrical electrode 65 with the cold ends 60 of the Joule-Thomson effect coolers 56 through-59 respectively abutting the outer periphery ofthe electrode 65, which may be a plate fora vacuum tube,as in the manner of Fig. 8. It -will be seen that in the arrangement of Fig. 11, the Joule-Thomson coolers 56 through 59 inclusive, in essence, form the spokes of a wheel with the header 62 forming the rim and the electrode 65 forming the hub; Here againythe low' pressure nitrogen discharge'line 63 is connected to-the header 62 and in the case of Fig. ,11, the highpressure nitrogen inlet line 64 is shown as being coaxially brought out within the low pressure discharge line 63.

Referring now to Fig. 12, yet another modification of my invention is shown in which a cylindrical electrode 65 is provided formed of relatively thick metal having high heat conductivity, such as copper. Secured to the bottom edge of the electrode 65 is a cylindrical member 66 formed of thinner metal having lower heat conductivity, such as stainless steel. The Joule-Thomson efiect cooler 67 is spirally wound around the sleeve 66 and the electrode 65 with its cold end 68 abutting the outer surface of the electrode 65 and with its warmer convolutions 69 and 70 abutting the sleeve member 66 and preferably attached thereto, as by spot welding at a plurality of points 71. Low pressure nitrogen discharge line 72 is brought out from the warm end 73 of the Joule- Thomson effect cooler 67 with high pressure nitrogen inlet line 74 being brought out coaxially within the low pressure nitrogen discharge line 72. Here, the weld points 71 are provided in order to insure intimate contact of the lower sleeve or wall 66 with the convolutions 69 and 70 of the Joule-Thompson effect cooler 67. With the arrangement of Fig. 12, the temperature is distributed between the warm end 75 of the sleeve 66 and the cold electrode 65 so that there is not an abrupt change between the ambient temperature and the cooled electrode 65; a transition region is thus provided by the sleeve 66 between the ambient temperature and the electrode 65.

It will now be seen that I have provided an arrange ment for internally cooling an electrode of an electron discharge device, such arrangement being adaptable for relatively small electron discharge devices and further permitting far greater heat extraction than that provided by prior cooling methods.

While I have described above the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention.

What is claimed is:

1. An electron discharge device'comprising an envelope; an electrode positioned within said envelope and having an external electrical connection thereto; a Joule- Thomson cooler positioned within said envelope and having a portion abutting said electrode; and connections for conveying high pressure liquid nitrogen to said cooler and low pressure gaseous nitrogen from said cooler extending respectively out of said envelope.

2. In an electron discharge device: an enclosing envelope; an electrode in said envelope; a Joule-Thomson cooler in said envelope having a portion thereof abutting said electrode; and connections for conveying high pressure liquid refrigerant to said cooler and low pressure gas from said cooler extending respectively out of said en- Velope.

3. In an electron discharge device: an electrode; a plurality of Joule-Thomson coolers respectively abutting said electrode; and a header member communicating with each of said coolers and having conduits for respectively conveying high pressure liquid refrigerant to said coolers and low pressure gas away from said coolers.

4. In an electron discharge device: an electrode; a plurality of Joule-Thomson coolers having their cold ends respectively abutting one surface of said electrode; and a header member communicating with the other ends of each of said coolers and having conduits for respectively conveying high pressure liquid nitrogen to said coolers andlow pressure nitrogen gasv away fromsaid coolers.

5. Inan'electron discharge device: van electrode having "a. circular dimension; and a semi-circular-shaped Joule-Thomson cooler embracing said electrode.

6. In an electron dischargedevice: an enclosing envelope; an electrode in said envelope; a Joule-Thomson efiect heat exchanger in said envelope having aneuclosing jacket with its cold portion abutting one surface of said electrode; and connections for conveying high pressure liquid refrigerant to said heat exchanger and low pressure gas from said heat exchanger extending respectively out of said envelope.

7. In an electron discharge device: anv enclosing envelope; a flat annular electrode in said envelope; a Joule- Thomson heat exchanger in said envelope having an enclosing jacket with its cold end abutting one side of said electrode; and connections for conveying high pressure liquid refrigerant to said heat exchanger and low pressure gas from said heat exchanger extending respectively out of said envelope.

8. In an electron discharge device: a flat annular electrode; and a semi-circular-shaped Joule-Thomson cooler embracing the periphery of said electrode.

9. In an electron discharge device: a cylindrical electrode; and a semi-circular-shaped Joule-Thomson cooler embracing the outer surface of said electrode.

10. In an electron discharge device: a flat annular electrode; a plurality of Joule-Thomson effect heat exchangers each having enclosing jackets with their cold ends respectively abutting one side of said electrode: a header member communicating with the other ends of each of said jackets and having conduits for respectively conveying high pressure liquid nitrogen to said heat exhangers and low pressure nitrogen gas away therefrom.

11. In an electron discharge device: a flat annular electrode; a plurality of Joule-Thomson coolers disposed in a circle and having their cold ends respectively abutting one side of said electrode adjacent its outer periphery; and substantially a toroidal-shaped header member communicating with the other ends of each of said coolers and having conduits for respectively conveying high pressure liquid nitrogen to said coolers and low pressure nitrogen gas away from said coolers.

12. In an electron discharge device: a flat annular electrode; a plurality of Joule-Thomson coolers having a frusto-conical arrangement and having their cold ends respectively abutting one side of said electrode adjacent its outer periphery; and a substantially toroidal shaped header member communicating with the outer ends of each of said coolers, and having conduits for respectively conveying high pressure liquid nitrogen to said coolers and low pressure nitrogen gas away from said coolers.

13. In an electron discharge device: a cylindrical electrode; a plurality of Joule-Thomson coolers disposed as spokes in a wheel and having their cold ends respectively abutting the outer surface of said electrode; and a substantially toroidal shaped header member communicating with the other end of each of said coolers and having conduits for respectively conveying high pressure liquid nitrogen to said coolers and low pressure nitrogen gas away from said coolers.

14. In an electron discharge device: a flat annular electrode; a plurality of Joule-Thomson cooling coils vertically disposed with respect to one side of said electrode; a cylindrical jacket member enclosing each of said coils, said electrode abutting one end of each of said jacket members adjacent the cool ends of said coils and forming a closure for said jacket members; conduit means for conveying high pressure liquid nitrogen to each of said coils; and conduit means for conveying low pressure nitrogen gas away from said jacket members.

15. In an electron discharge device: a cylindrical elec- References Cited in the file of this patent UNITED STATES PATENTS 859,092 Massie July 2, 1907 2,536,001 Chase Dec. 26, 1950 2,587,075 Tice Feb. 26, 1952 

